Hi, I recently installed my new 16ch Hikvision Cctv kit , but there's one problem. On one of the ports the screen is black, I know usually it would say 'no video' but now it isn't it's just a black screen that even by double clicking you can't enlargen, there is nothing blocking the camera and when I change the camera to a different port the camera is working. So can anyone advise as how to fix this?